Manufacture and sale of athletic goggles and masks is a multi-million dollar industry world-wide. Ski masks, swim goggles and the like are designed to protect a user's eyes from injury and uncomfortable contact with water or air. This is achieved by providing the goggles or mask with an air tight seal that conforms to the user's face to create pockets of air around the user's eyes, and thereby separate the eyes from the harsh external medium.
Notwithstanding the large number of different types of goggles and masks offered to the public, all suffer from a recurrent and bothersome problem: the deposition of minute water droplets, commonly known as "fogging," on the interior surface of the eye pieces. Fogging generally occurs because of a temperature differential between the mask or goggles, which tend to attain the temperature of the external medium, and the pockets of air trapped within the goggles, which tend to remain at a temperature closer to the skin temperature of the user. Water vapor in the trapped air pockets cools upon contact with the cooler surfaces of the goggles and condenses as water droplets on these surfaces. The problem is further exacerbated by the fact that moisture from the skin, and more particularly the ocular surface, of the user evaporates during athletic activity, saturating the trapped air with more water vapor even as pre-existing water vapor is lost as droplets through condensation.
Fogging is problematic because it results in a significant loss of visibility, requiring the user to cease athletic activity frequently in order to defog the goggles or mask manually. This is particularly disadvantageous during an athletic competition where the loss of even a few seconds can result in the loss of a race.
Although many solutions have been proposed to the fogging problem, none is without significant drawbacks. For example, it is known that coating the lens with a thin film of a hydrophobic material, such as oil or soap residue, can alleviate problems with fogging. However, such materials frequently impair visual acuity through the lens and require frequent reapplication. U.S. Pat. Nos. 4,972,521 to Lison and 4,414,693 to Brody each describe eyewear comprising lenses coated with more permanent anti-fogging material. Although overcoming the reapplication problem, fogging is not completely eliminated. Furthermore such manufactures are too difficult and expensive to produce for applications that do not require a high degree of optical precision, such as prescription eye glasses and the like.
Others have approached the fogging problem by designing intricate assemblies in an attempt to isolate fog-prone lens surfaces from the conditions that promote fogging, such as extreme temperature differentials between the interior and exterior of masks and goggles. U.S. Pat. Nos. 3,591,864 to Allsop and 5,018,223 to Dawson et al., which teach the use of spaced apart lenses, are illustrative of this approach. Such constructions are extremely costly to produce and too delicate to employ in active wear such as athletic goggles and masks.
In view of long the long felt need within the industry to solve the fogging problem and the short-comings inherent in the prior art, there is clearly a need for a safe, effective, and affordable means of eliminating fogging in athletic goggles and masks. Such a solution should not only be effective, but it must be efficient to manufacture, cost-effective to produce, and carefree to use. It must also be easy to adapt for use in retrofitting the many millions of existing goggles and masks currently in use.